Field of the Invention
The present invention relates to a technology for calculating an insertion length at which an insertion unit of an endoscope apparatus is inserted into a subject in an endoscope system.
Description of the Related Art
Endoscopy includes upper endoscopy and lower endoscopy. In both the upper endoscopy and the lower endoscopy, when a distal end of an insertion unit of an endoscope apparatus reaches an examination region within a body cavity of a patient who is a subject, an operator of an endoscope starts an examination and various processes relating to the examination. An insertion length (amount) of the endoscope apparatus is generally determined by a doctor who is an operator from an observation image captured by using the endoscope apparatus on the basis of the doctor's experience or the like. Therefore, it may be difficult for an inexperienced resident or the like or a third party to easily grasp a photographed portion (an examination region) by only viewing an observation image.
As a known technology, a technology for observing the shape of an insertion unit of an endoscope apparatus within a body cavity has been proposed. According to this technology, the insertion unit of the endoscope apparatus incorporates a plurality of magnetic coils. A coil unit that is a position detector receives magnetism generated from the plurality of magnetic coils, and as a result, the shape of the insertion unit is obtained. As an example, Japanese Laid-Open Patent Publication No. 2010-88573 discloses a technology for calculating a distance from a position (a base point) in which an insertion unit starts to come into contact with a subject to a distal end of the insertion unit, namely, an insertion length of an endoscope apparatus, by using the technology above.